Nine presenter Peter Stefanovic revealed on Saturday that he has struggled with loneliness in the past, and urged others going through the same thing to seek support.

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The Weekend TODAY hosts were discussing the loneliness epidemic with psychologist Sandy Rea.

"I don't want to talk about myself, but Sandy, I've had problems with this," Stefanovic said. During his time as a London correspondent for Channel Nine, he explained, he lived alone for long periods of time, and often found himself stuck at home with no one to talk to.

"You have these problems," he said.

(Channel Nine)

"I have spent a good portion of my time in the corner of a pub with no one to talk to – and I'm quite a shy person."

Co-host Allison Langdon observed that this kind of environment could be "incredibly isolating".

"Yes, it can be," Stefanovic agreed. "I've got good family and good friends, but when you're a long, long way from home, when you're working odd hours of the day too ... it can be trouble."

"You can see why when people are alone, that that can lead to some kind of depression," he continued, looking visibly upset.

(Channel Nine)

"It's [a case of] one thing can lead to another."

Stefanovic then caught himself with a joke.

"It's very big downer for this morning," he said to Langdon. "Let's try and lift the mood."

Jokes aside, Rea noted that in Australia, men are most at risk of the adverse effects of loneliness. Men 85 and above have the highest rates of suicide in the country, followed by men 30-34, and men 40-54.

(Channel Nine)

"Men suffer the most: physically, mentally, emotionally," Rea said.

"Persistently and consistently, men suffer from loneliness in Australia. They are the most at-risk population."

(Channel Nine)

Studies have revealed that loneliness can have similar negative impacts on the body to 15 cigarettes per day. Rea said other physical symptoms can manifest in poor sleep, obesity, suppression of the automimmune system and even cardiovascular disease.

"When we feel lonely, we're feeling a real sense of social pain," she said. "There's actually a heart ache involved."

It's becoming such a serious health issue globally that the UK has gone as far as to appoint a minister.

Australia doesn't currently have a nationally coordinated approach, but Rea said healthcare professionals are focused on short-term interventions such as 'nostalgia therapy', where patients reflect on past successful relationships and what made them work.

"[It's] making the decision to up your social skills," she said: changing posture, voice and eye contact, and trying to step back from the sense of 'hypervigilance' that causes lonely people to see all social gatherings and personal interactions as threatening situations.

"Loneliness is not just about being with people," Rea said. "You can be surrounded by lots of people but feel, 'No one cares for me, no one concerns themself with me.'"

We've all felt loneliness – though perhaps not to such serious extents. But as with so many things, the first step to helping those who are struggling is to talk about it.